GL-MiFi : mPCIe & external USB?

On the GL-MiFi, the mPCIe connector is USB only (or does it have PCIe signals as well) ?

Most WWAN cards use USB, so can I use a WWAN card and the external USB at the same time ?

it is only USB.

It only has one USB-A port. You can use the MicroSD slot for storage.